The present invention relates to a novel compound suitable for use as a dye for a filter, a color conversion filter, a dye for a photographic material, a sensitizing dye, a dye for pulp dyeing, a laser dye, a fluorescent medicine for a medical diagnosis, a material for an organic luminescence element, etc., and an organic luminescence element using the same.
Prospects of an organic luminescence element in which organic materials are used are promising as a solid luminescent type inexpensive and large area full color display element and development has been tried variously. In general, an organic luminescence element comprises a luminescent layer and a pair of counter electrodes with the luminescent layer between. When electric field is impressed between both electrodes, electrons are injected from the cathode and positive holes are injected from the anode, and the electrons and positive holes are recombined in the luminescent layer. A phenomenon of emitting energy as light when energy level is returned from conduction band to valence band is luminescence.
Organic luminescence elements so far been used require high driving voltage and luminance and luminescent efficacy are low, but various techniques for improving these points are reported in recent years. For example, there is known a luminescence element comprising organic thin layers formed by vapor deposition of organic compounds (Applied Physics Letters, Vol. 51, p. 913 (1987)). This organic luminescence element comprises the lamination structure of an electron-transporting material and a positive hole-transporting material, and the luminescent characteristics have been remarkably improved as compared with conventionally used single layer type elements.
Al complex of 8-quinolinol (Alq) is used as a luminescent material in the above element and a luminescent color is green, but when taking into consideration the utilization as a full color display and a light source, it is necessary to get three primary colors or a white color in practical use. As the improved element thereof, an element to which a fluorescent dye is doped is reported (Journal of Applied Physics, Vol. 65, p. 3610 (1989)). According to the above report, reddish orange luminescence is obtained by doping 4-(dicyanomethylene)-2-methyl-6-(4-dimethylamino-styryl)-4-H-pyran (DCM), but this element is impracticable as color purity is low and durability is low. Similarly, although various organic luminescence elements which emit light in longer wavelength range than green have been developed by doping fluorescent materials, any of these elements has serious drawbacks that color purity is low as red luminescence and sufficient luminance cannot be obtained. Further, there is another problem that organic luminescence elements in which conventional red fluorescent dyes are used exhibit low durability.
Further, conventionally used elements which have excellent color purity and high luminescent efficacy are those having been doped with a small amount of a fluorescent dye in an electric charge-transporting material. Such elements have drawbacks that characteristics of elements are difficult to be reproduced from the manufacturing technique and the durability of the dye is low, as a result, the luminance is reduced or the color changes after being used for a long period of time. To cope with these problems, development of a material which functions as an electric charge-transporting material and a luminescent material in one has been desired. However, with materials so far been developed, when a fluorescent dye is used in high concentration as an electric-transporting material, emission with high luminance is difficult as quenching due to concentration occurs.
On the other hand, organic luminescence elements which have realized high luminance emission are laminated elements formed by vacuum deposition of organic materials, but from the viewpoint of simplification of producing step, processability, and realization of large area elements, it is desired to produce elements by a coating system. However, elements produced by a coating system so far been used are inferior to those produced by a vapor deposition system in luminance and luminescent efficacy, therefore, high luminance and luminescence with high efficacy have been left as problems to be solved.
Further, in recent years, various materials having fluorescence have been used in a dye for a filter, a color conversion filter, a dye for a photographic material, a sensitizing dye, a dye for pulp dyeing, a laser dye, a fluorescent medicine for a medical diagnosis, a material for an organic luminescence element, etc., and demand for such materials has been increased. However, red fluorescent dyes having high fluorescent strength and high color purity are less, therefore, the development of a novel material has been desired.
A first object of the present invention is to provide a red fluorescent compound having high color purity and to provide an organic luminescence element using the same.
A second object of the present invention is to provide a material for an organic luminescence element capable of emission of high luminance and high efficacy by low voltage-driving and excellent in stability by repeating use, and to provide an organic luminescence element using the same.
A third object of the present invention is to provide a material emitting a red color necessary to realize white luminescence and to provide an organic luminescence element using the same.
A fourth object of the present invention is to provide a material for an organic luminescence element capable of emission of high luminance and high efficacy even when produced by a coating system and to provide an organic luminescence element using the same.
A fifth object of the present invention is to provide a compound having high fluorescent strength in a reddish orange to near infrared region.
The above objects of the present invention have been achieved by the following means.
(1A) A methine compound represented by the following formula (I): 
wherein R1, R2, R3, R4 and R5 each represents a hydrogen atom or a substituent; X represents an oxygen atom, a sulfur atom, or Nxe2x80x94R6; Z represents xe2x80x94NR7R8, or xe2x80x94OG; R6, R7 and R8 each represents a hydrogen atom or a substituent; G represents a hydrogen atom, a cation or a substituent; L1, L2 and L3 each represents a substituted or unsubstituted methine group; n represents 1 or 2; and W represents an electron attractive group (electron withdrawing group).
(2A) A methine compound represented by the following formula (I-a): 
wherein R1, R2, R3, R4, R5, R7 and R8 each represents a hydrogen atom or a substituent; L1, L2 and L3 each represents a substituted or unsubstituted methine group; n represents 1 or 2; and W represents an electron attractive group.
(3A) A methine compound represented by the following formula (I-b): 
wherein R1, R2, R3, R4, R5, R7, R8, Rb1, Rb2, Rb3 and Rb4 each represents a hydrogen atom or a substituent; and Wb1 and Wb2 each represents an electron attractive group.
(4A) A methine compound represented by the following formula (I-c): 
wherein R1, R2, R3, R4, R5, R7, R8, Rb1, Rb2, Rb3 and Rb4 each represents a hydrogen atom or a substituent.
(5A) A methine compound represented by the following formula (I-d): 
wherein R1, R2, R3, R4, R5, R7, R8, Rb1, Rb2, Rb3 and Rb4 each represents a hydrogen atom or a substituent; and Q represents an atomic group necessary for forming a 5- or 6-membered ring.
(6A) A methine compound represented by the following formula (I-e): 
wherein R1, R2, R3, R4, R5, R7, R8, R1b, Rb2, Rb3 and Rb4 each represents a hydrogen atom or a substituent; and Qe represents an atomic group necessary for forming a 5- or 6-membered ring.
(7A) A material for an organic luminescence element which is represented by formula (I), (I-a), (I-b), (I-c), (I-d) or (I-e) as described in the above item (1A), (2A), (3A), (4A), (5A) or (6A).
(8A) An organic luminescence element comprising a pair of electrodes having formed therebetween a luminescent layer or a plurality of organic compound thin layers including a luminescent layer, wherein at least one layer is a layer containing a methine compound represented by formula (I), (I-a), (I-b), (I-c), (I-d) or (I-e) as described in the above item (1A), (2A), (3A), (4A), (5A) or (6A).
(9A) An organic luminescence element comprising a pair of electrodes having formed therebetween a luminescent layer or a plurality of organic compound thin layers including a luminescent layer, wherein at least one layer is a layer having dispersed in a polymer a methine compound represented by formula (I), (I-a), (I-b), (I-c), (I-d) or (I-e) as described in the above item (1A), (2A), (3A), (4A), (5A) or (6A).
(1B) A material for an organic luminescence element which is a compound represented by the following formula (II): 
wherein R1, R2, R3, R4, R5, R6, R7, R8 and R9 each represents a hydrogen atom or a substituent; X represents an oxygen atom, a sulfur atom, or Nxe2x80x94R10 (wherein R10 represents a hydrogen atom or a substituent); Z1 represents an atomic group necessary for forming a 5- or 6-membered ring; L1 and L2 each represents a substituted or unsubstituted methine group; and n represents 1 or 2.
(2B) A material for an organic luminescence element which is a compound represented by the following formula (III): 
wherein R1, R2, R3, R4, R5, R6, R7, R8 and R9 each represents a hydrogen atom or a substituent; Z2 represents an atomic group necessary for forming a 5- or 6-membered ring; L1 and L2 each represents a substituted or unsubstituted methine group; and n represents 1 or 2.
(3B) A compound represented by the following formula (IV): 
wherein R1, R2, R3, R4, R5, R6, R7 and R8 each represents a hydrogen atom or a substituent; R31 represents an alkyl group having 2 or more carbon atoms, or an aryl group having 6 or more carbon atoms; Z2 represents an atomic group necessary for forming a 5- or 6-membered ring; L1 and L2 each represents a substituted or unsubstituted methine group; and n represents 1 or 2.
(4B) A material for an organic luminescence element which is a compound represented by the following formula (IV): 
wherein R1, R2, R3, R4, R5, R6, R7 and R8 each represents a hydrogen atom or a substituent; R31 represents an alkyl group having 2 or more carbon atoms, or an aryl group having 6 or more carbon atoms; Z2 represents an atomic group necessary for forming a 5- or 6-membered ring; L1 and L2 each represents a substituted or unsubstituted methine group; and n represents 1 or 2.
(5B) A compound represented by the following formula (IV-a): 
wherein R1, R2, R3, R4, R5, R6, R7, R8, R41, R42, R43 and R44 represents a hydrogen atom or a substituent; R31 represents an alkyl group having 2 or more carbon atoms, or an aryl group having 6 or more carbon atoms; L1 and L2 each represents a substituted or unsubstituted methine group; and n represents 1 or 2.
(6B) A material for an organic luminescence element which is a compound represented by the following formula (IV-a): 
wherein R1, R2, R3, R4, R5, R6, R7, R8, R41, R42, R43 and R44 each represents a hydrogen atom or a substituent; R31 represents an alkyl group having 2 or more carbon atoms, or an aryl group having 6 or more carbon atoms; L1 and L2 each represents a substituted or unsubstituted methine group; and n represents 1 or 2.
(7B) A compound represented by the following formula (V): 
wherein R1, R2, R3, R4, R5, R6, R7, R8, R9, R51, and R52 each represents a hydrogen atom or a substituent; L1 and L2 each represents a substituted or unsubstituted methine group; and n represents 1 or 2.
(8B) A material for an organic luminescence element which is a compound represented by the following formula (V): 
wherein R1, R2, R3, R4, R5, R6, R7, R8, R9, R51, and R52 each represents a hydrogen atom or a substituent; L1 and L2 each represents a substituted or unsubstituted methine group; and n represents 1 or 2.
(9B) An organic luminescence element comprising a pair of electrodes having formed therebetween a luminescent layer or a plurality of organic compound thin layers including a luminescent layer, wherein at least one layer is a layer containing a compound represented by formula (II), (III), (IV), (IV-a) or (V) described in the above item (1B), (2B), (4B), (6B) or (8B).
(10B) An organic luminescence element comprising a pair of electrodes having formed therebetween a luminescent layer or a plurality of organic compound thin layers including a luminescent layer, wherein at least one layer is a layer having dispersed in a polymer a compound represented by formula (II), (III), (IV), (IV-a) or (V) described in the above item (1B), (2B), (4B), (6B) or (8B).
(1C) A methine compound represented by the following formula (VI): 
wherein R1, R2, R3, R4, R5, R6, R7, R8, R9 and R each represents a hydrogen atom or a substituent; A represents a heterocyclic ring containing an aromatic ring; X represents an oxygen atom, a sulfur atom, or Nxe2x80x94R10 (wherein R10 represents a hydrogen atom or a substituent); L1 and L2 each represents a substituted or unsubstituted methine group; and n represents 1 or 2.
(2C) A material or an organic luminescence element represented by formula (VI) described in item (1C).
(3C) An organic luminescence element comprising a pair of electrodes having formed therebetween a luminescent layer or a plurality of organic compound thin layers including a luminescent layer, wherein at least one layer is a layer containing a methine compound described in item (1C).
(4C) An organic luminescence element comprising a pair of electrodes having formed therebetween a luminescent layer or a plurality of organic compound thin layers including a luminescent layer, wherein at least one layer is a layer having dispersed in a polymer a methine compound described in item (1C).